Prepackaging of reagents into kits has created a paradigm shift in biological assays. More specifically, the prepackaging of reagents has made it easier to sell reagents and easier for the end-user to perform an assay. In view of the foregoing, there has developed an ever increasing precedence towards prepackaging and utilizing reagents at even lower volumes, e.g., on the micro and nano liter scales. This creates an incentive and a challenge in the adoption of microfluidic technologies. The capability of prepackaging fluids in ways that are directly compatible with already existing automation techniques would significantly lower operational cost and accelerate assay times, thereby further reducing costs. By way of example, polymerase chain reaction (PCR) assays require on instrument reagent preparation followed by the dispensing of hundreds of small (few microliter) volumes.
One simple way to prepackage reagents would be to provide the reagents directly in a pipette tip. It can be appreciated that a process of prepackaging reagents in a pipette tip is fundamentally simple. Further, such a process does not require any modification to already existing pipette tips. However, pipette tips with prepackaged therein are not directly compatible with commercially available pipettes and pipetting instruments. As is known, current pipettes are comprised of a sealed chamber and a plunger. The plunger displaces air to aspirate and dispense fluids, and as such, forms an air-tight seal in the chamber. Disposable tips are installed onto the pipette by pressing the pipette into the tip. During this installation, the pipette actually displaces air in the pipette tip, forcing the air through the orifice of the pipette tip. This air displacement does not cause any issues when the tip is empty. However, if a fluid were to be stored in the tip, this displacement will force fluid out of the tip. As such, there exists a need for a non-displasive pipette having a tip for allowing reagents, analytes and the like to be prepackaged therein.
Therefore, it is a primary object and feature of the present invention to provide a non-displasive pipette having a tip for allowing reagents, analytes and the like to be prepackaged therein.
It is a further object and feature of the present invention to provide a non-displasive pipette having a tip for allowing reagents, analytes and the like to be prepackaged therein that is simple to utilize and inexpensive to manufacture.
It is a still further object and feature of the present invention to provide a non-displasive pipette having a tip for allowing reagents, analytes and the like to be prepackaged therein that is compatible with existing automation techniques.
In accordance with the present invention, a non-displasive pipette configured for connection to a tip having prepackaged fluid therein is provided. The non-displasive pipette includes a body having a tubular wall with an inner surface defining a chamber extending through the body between first and second ends thereof and an outer surface. A plunger is slidably received in a first end of the chamber of the body. The plunger is moveable along the inner surface of the tubular wall between a first extended position and a second depressed position. An air escape passage extends through at least one of the tubular wall of the body and the plunger. The chamber communicates with an environment outside of the pipette through the air escape passage with the plunger in the extended position. Alternatively, communication between the chamber and the environment outside of the pipette through the air escape passage is prevented with the plunger in the extended position.
The tip is receivable on the second end of the body and the fluid prepackaged in the tip remains therein in response to movement of the plunger from the extended position to the depressed position. The tip includes an orifice and the plunger is movable to a third discharge position wherein the fluid prepackaged in the tip is urged from the tip. A seal may extend about the plunger and forming a sealing interface with the inner surface of the tubular wall. The plunger includes a first end, a second end receivable in the chamber of the body and an outer surface. In a first embodiment, the air escape passage extends between the first end of the plunger and the outer surface of the plunger at a first location and the seal extends about the outer surface of the plunger between the first location and the first end of the plunger. In an alternate embodiment, the air escape passage extends through the tubular wall between the inner and outer surfaces thereof.
An air seal may be positioned along the outer surface of the tubular wall. The air seal is movable between a first closed position wherein the air seal overlaps an intersection of the air escape passage and the outer surface of the tubular wall so as to prevent a flow of air through the air escape passage and a second open position wherein the air escape passage is allowed to communicate with the environment outside of the pipette. A biasing structure may urge the air seal towards the closed position. Alternatively, the air seal may include a collar extending about the outer surface of the tubular wall. Rotation of the collar moves the air seal between the first closed position and the second open position.
In accordance with a further aspect of the present invention, a non-displasive pipette is provided. The non-displasive pipette is configured for connection to a tip having a fluid prepackaged therein. The tip includes an orifice to allow for the discharge of the fluid therefrom. The non-displasive pipette includes a body defining a chamber therethrough and having first and second opposite ends. The second end of the body is configured for connection to the tip. A plunger is slidably received in the first end of the chamber of the body. The plunger is moveable in the chamber between a first extended position and a second depressed position. An air escape passage extends through at least one of body and the plunger. The air escape passage is configured to allow air from the chamber to escape therefrom in response to connection of the tip to the second end of the body.
It is contemplated for the chamber to communicate with an environment outside of the pipette through the air escape passage with the plunger in the extended position. The chamber is isolated from the environment outside of the pipette through the air escape passage with the plunger in the depressed position. The fluid prepackaged in the tip remains therein in response to movement of the plunger from the extended position to the depressed position. The plunger is movable between the second depressed position and a third discharge position. The fluid prepackaged in the tip is urged from the tip through the orifice in response to movement of the plunger from the depressed position to the discharge position.
A seal may extend about the plunger and form a sealing interface with the body. The plunger includes a first end, a second end receivable in the chamber of the body and an outer surface. The air escape passage may extend through the plunger and intersects the outer surface of the plunger at a first location. The seal extends about the outer surface of the plunger between the first location and the first end of the plunger. Alternatively, the air escape passage may extend through the body.
An air seal may be positioned along an outer surface of the body. The air seal is movable between a first closed position wherein the air seal overlaps an intersection of the air escape passage and the outer surface of the body and prevents a flow of air through the air escape passage and a second open position wherein the air escape passage is allowed to communicate with the environment outside of the pipette. A biasing structure may be provided for urging the air seal towards the closed position. Alternatively, the air seal may include a collar extending about the outer surface of the body. Rotation of the collar moves the air seal between the first closed position and the second open position.
In accordance with a still further aspect of the present invention, a non-displasive pipette is provided. The non-displasive pipette is configured for connection to a tip having a fluid therein. The tip includes an orifice to allow for the discharge of the fluid therefrom. The non-displasive pipette includes a body defining a chamber therethrough and having first and second opposite ends. The second end of the body is configured for connection to the tip. A plunger is slidably received in the chamber at the first end of the body. The plunger is moveable in the chamber between an extended position and a discharge position wherein the fluid is urged from tip through the orifice. An air discharge arrangement is configured to allow air from the chamber to escape therefrom and to maintain the fluid in the tip in response to connection of the second end of the body to the tip.
The plunger is movable to a depressed position at a location between the extended position and the discharge position. The fluid in the tip is maintained therein in response to movement of the plunger from the extended position to the depressed position. A seal may extend about the plunger and forming a sealing interface with the body. The plunger includes a first end, a second end receivable in the chamber of the body and an outer surface. The air discharge arrangement may include an air escape passage extending between the first end of the plunger and the outer surface of the plunger at a first location. The seal extends about the outer surface of the plunger between the first location and the first end of the plunger. Alternatively, the air discharge arrangement includes an air escape passage extending through the body. An air seal is positioned along an outer surface of the body. The air seal is movable between a first closed position wherein the air seal prevents air from the exiting the chamber and a second open position wherein the air seal allows to exit the chamber. A biasing structure may be provided for urging the air seal towards the closed position. Alternatively, the air seal may include a collar extending about an outer surface of the body. Rotation of the collar moves the air seal between the first closed position and the second open position.